There will not be any consensus between Beijing and Hong Kong’s democratic camp on universal suffrage in the next 20 years, an adviser from a top think tank said on Thursday.

Lau Siu-kai, a former head of the government’s Central Policy Unit, pointed out that the central government had already laid down its directive on how the matter should be approached and considered the issue “solved”.

Lau, now vice-president of the Chinese Association of Hong Kong and Macau Studies – a Beijing-associated think tank – said it was now up to the opposition camp to accept the terms.

Lau told RTHK that a framework laid down by the National People’s Congress Standing Committee – Beijing’s top lawmaking body – in August 2014 already stipulated conditions for future chief executive and Legislative Council elections.

“Unless [Beijing] changes its mind, electing the chief executive by means of universal suffrage can be done only under this framework,” he said.

The 2014 decision sets tight restrictions on candidates by retaining an exclusive pro-Beijing nomination committee, which effectively screens out unfavourable chief executive candidates before allowing 3 million voters in Hong Kong to cast their ballots.

It also retained the current composition of the 70-member Legco, in which 35 seats belong to the functional constituencies, dominated by Beijing loyalists.

“It depends how you define universal suffrage – one that fulfils Western values, or one that conforms to the Basic Law and the ‘one country, two systems’ principle?”

Watch: What is the Basic Law?

The Basic Law is the city’s mini-constitution, and one country, two systems is the model under which Beijing rules it.

Lau said both sides are “poles apart” on this matter, and that he fears no common ground can be reached in the next 20 years.

The only exception, he predicted, would be if the opposition camp earned Beijing’s trust by pledging allegiance to the mainland’s constitution and the Basic Law, and no longer aimed to overthrow the central government.

Lau touched on other topics, such as Zhang Dejiang stepping down as head of the Central Coordination Group for Hong Kong and Macau Affairs.

He said Beijing’s policies governing the two special administrative regions had “matured”, so there was no need to be overly anxious about who would replace the former No 3 state leader in charge of the city’s affairs.

But Lau feared the revamped unit and its new name could lead to confusion among mainland officials and even create the impression that the body was being downgraded.

Democratic Party lawmaker James To Kun-sun criticised Lau’s “negative” comments, even accusing Lau of trying to pressure the Hong Kong government against restarting the political reform process.

The comments not downplayed the chances of achieving democratic elections but also tried to portray the process as a done deal and prevented both sides from finding common ground, To added in a statement.

The lawmaker said he remained confident that Beijing’s new leadership would listen to Hongkongers and work out a feasible universal suffrage proposal.